Once the natural driving force has been depleted oil or hydrocarbonaceous fluids must be removed from a formation via enhanced oil recovery methods. Some of these enhanced oil recovery methods where fracturing is employed utilize foams, gels, water, or other fluids which can also damage the formation and impede the recovery of hydrocarbonaceous fluids. Indeed, some of these fluids (fracture fluid load) can cause permanent damage to a formation. Once fracture fluid has served its purpose, it is necessary to remove it to continue producing hydrocarbonaceous fluids from the formation.
Methods are available to the oil producing industry for removing or lifting these spent load fluids from the reservoir. In one of these methods, stimulation fluids using foam (nitrogen and water, nitrogen and hydrocarbons, carbon dioxide and water, and carbon dioxide and hydrocarbons) have also been developed by service companies which provide built-in gas assist. Also nitrogen or carbon dioxide can be added as a gas "on the fly" during stimulation treatments.
Drawbacks to the use of gas assist include: economics (addition of gases adds to the expense of well stimulation) equipment (special equipment is required to handle gas on the surface prior to the treatment for pumping during the treatment); availability (remote areas where gas sources and handling equipment are not available); and safety (pumping at high pressures can be dangerous).
Therefore, what is needed is a method that overcomes the economy, equipment, availability, equipment, and safety drawbacks associated with prior art gas assist methods for removing residue drive fluids, spent fracturing fluids, and treating fluids from a reservoir.